1. Field of the Invention
The present invention relates to an arrangement of permanent magnets that separates particles from a solution in a vessel, as utilized in the field of biology to remove cells from a sample contained in a test tube or the like.
2. Description of the Related Art
Co-pending patent application Ser. No. 08/868,598, filed in the U.S. Patent and Trademark Office on Jun. 4, 1997, now U.S. Pat. No. 6,451,207 describes a magnetic device that surrounds a vessel, such as a test tube, containing a liquid sample. The liquid sample may be a colloidal suspension or at least a fluid mixture. The magnetic device provides an external magnetic field within a liquid sample for the purpose of causing separation of magnetized particles or cells from the liquid sample. The magnetic device has four polar magnets and a plurality of interpolar magnets positioned to provide an external magnetic field having a high flux density gradient within the liquid sample. However, the uniform magnetic field gradient generated within the liquid sample impedes the ability to easily pour off the liquid after a significant amount of cell separation has occurred, without suffering the loss of magnetized particles as well. Moreover, the magnet structure, in surrounding the vessel, fails to provide a viewing window through which to view the liquid sample, for example, to detect the degree of separation of the magnetized particles from the liquid sample.
An apparatus for biological particle separation, comprising a vessel containing a plurality of biological particles suspended in a liquid. The vessel has a proximate open end, and a distal closed end. A number of magnetic beads are biologically attached to the biological particles. The beads, generally spherical, may range from 50 nanometers to 10 microns mean diameter. The magnet structure substantially surrounds all but a portion of a wall of the vessel to draw the particles to the wall of the vessel and allow the liquid to be poured off the portion of the wall not surrounded by the magnet structure, without losing the magnetic beads and particles attached thereto.